Lead sharpening device



July 30, 1963 c. R. TAYLOR LEAD SHARPENING DEVICE 2 Sheets-Sheet 1 Filed May .22, 1961 CLARENCE R TAYLOR INVENTOR.

By UM ATTORNEY July 30, 1963 c. R. TAYLOR LEAD SHARPENING DEVICE 2 Sheets-Sheet 2 File'd May 22, 1961 Fig. 6

CLARENCE R. 7J4YLOI? IN V EN TOR.

ATTORNEY United States Patent 3,099,253 LEAD SHARPENIN G DEVICE Clarence R. Taylor, Rochester, N.Y. (28 Woodside Drive, Penfield, N.Y.) Filed May 22, 1961, Ser. No. 111,710 2 Claims. (Cl. 120-94) This invention relates generally to grinding mechanisms, and more specifically to an automatic motorized sharpening device for sharpening the end portions of thin and relatively brittle elongated cylindrical elements such as drafting leads confined within a drafting pencil or compass.

The primary object of the present invention is to provide an improved motorized lead sharpening device that is of simple design and construction, thoroughly reliable and efficient in operation, and economical to manufacture.

Another object of this invention is to provide an improved motor-driven sharpening device for lead or the like which does not produce objectionable noise while in operation.

A further object of the invention is to provide an improved sharpening device for lead or the like which re tains all of the material which is removed from the sharpened object and may be easily emptied.

Yet another object of the invention is to provide an improved sharpening device for lead or the like incorporating abrasive members which are inexpensive and readily replaceable.

Another object of this invention is to provide an improved motorized sharpening device for lead or the like which will provide long, trouble-free service.

Still another object of this invention is to provide a motorized sharpening device for lead or the like in which the motor is protected from the filings removed from the sharpened objects.

A more specific object of this invention is to provide an improved motorized sharpening device for lead or the like having a unitary reciprocable table resiliently mounted and biased by a spring into engagement with a driving mechanism.

Objects and advantages other than those set forth above will be apparent from the following description when read in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of a sharpening device for lead or the like in which the present invention is embodied;

FIG. 2 is an enlarged plan view partly in section of the sharpening device of FIG. 2 taken along line 2-2;

FIG. 3 is a section view of FIG. 2;

FIG. 4 is a plan view of the table;

FIG. 5 is an end elevation view of the table of FIG. 4;

FIG. 6 is a section view taken along line 66 of FIG. 4;

FIG. 7 is a section view taken along line 7-7 of FIG. 4;

FIG. 8 is a segmental section view taken along line 88 of FIG. 4;

FIG. 9 is a segmental view of a portion of the sharpening device of FIG. 1 showing a novel switch mechanism which is in an open position;

FIG. 10 is a view similar to FIG. 9 showing the cover of the sharpening device in an open position, and the switch mechanism in a closed position;

FIG. 11 is a segmental bottom view of the switch mechanism of FIG. 9; and

FIG. 12 shows an electric circuit wiring diagram for the sharpening device of this invention.

As shown in the drawings, a preferred embodiment of a sharpening device 13 for lead or the like is disclosed,

Patented July 30, 1963 which is essentially an improvement in the sharpening device disclosed in US. Patent 2,791,986.

More specifically with reference to FIGS. 1 and 3, the sharpening device 13 comprises a base 14 having a peripheral upturned lip 15, and a cup-shaped housing 16 mounted on base 14 with its outer edge co-operating with lip 15 to form an enclosure. The edge of housing 16 and lip 15 may be cemented together to form a completely sealed enclosure, or if desired, housing 16 may be provided with slots 17 co-operating with screws 18 carried by base 14 for releasably securing housing 16 to base 14. A rubber pad 19 or similar material may be cemented to base 14 as best seen in FIG. 3 to minimize the tendency of sharpening device 13 to move on its supporting surface, and further to absorb noise and vibrations produced by device 13.

An electric motor 21 of conventional type is mounted on base 14 and essentially comprises a laminated metal stator 22, a portion of which is encircled by *a coil 23. The motor 21 further has a rotatable rotor 24 having a shaft 25 at one end provided with an eccentric pin 26 for a purpose to be explained hereinafter. Since this motor 21 and its mountings are substantially identical to the motor disclosed in the afore-mentioned patent, and is explained in detail therein, the structure is referred to only generally in this case.

The housing 16 of sharpening device 13 has a cover 27 as best seen in FIGS. 1, 3, 9 and 10 that is pivotally mounted about a rod 28 lying in a groove at one end of cover 27 closed off by a plug 29, the extending ends of rod 28 being supported in bosses, not shown, in housing 16. The hinged end of cover 27 further has two fiat surfaces 31, 32 at right angles to one another, one of which is spaced a further distance from the axis of rod 28 than the other. A switch 33 for motor 21 comprises a first leaf spring 34 having one end 35 mounted on the underside of housing 16, and its other spring end 36 adapted to selectively co-operate with one of the fiat surface 31, 32 for holding cover 27 in its closed or open position respectively, as seen best in FIGS. 9 and 10. An electric wire 37 interconnects end 36 of leaf spring 34 to motor 21 as seen best in FIGS. 11 and 12. The switch 33 further comprises another leaf spring 38 having one end 39 extending through an opening 41 provided by plug 42 cooperating with spaced apart bosses 43, 44 in housing 16, and turned through an angle of and secured to the outer surface of plug 42 as seen in FIG. 9. An insulating strip 45 is interposed between leaf springs 34, 38 to prevent any shorting therebetween. The opposite end 46 of leaf spring 38 is free and substantially parallel to a portion of leaf spring 34, and both leaf springs have registering contacts 47, 48. An electric Wire 49 of the normal type electrically connects end 39 of leaf spring 38 to one line of a power plug 51. As indicated earlier, one of the flat surfaces 33 of cover 27 is further removed from the axis of rod 28 than surface 31 so that in the closed position as seen in FIG. 9, the contacts 47, 48 are separated and motor 21 is unenergized. When cover 17 is opened, on the other hand, as seen in FIG. 10, the contacts 47, 48 are urged into engagement completing the electrical circuit to motor 21 which is energized, assuming that power plug 51 is inserted in a suitable power supply receptacle.

The sharpening device 13 further has a unitary member 52 as best seen in FIGS. 4-8 molded from some suitable material such as nylon or the like. The member 52 has a substantially rectangular table 53 having overhanging lips 54 at one side underneath which an edge of a rectangular sheet of sandpaper 55 is inserted. The corners of the opposite edge of the sheet of sandpaper 55 are bent and inserted in triangularly-shaped slots 56 in table 53 for releasably holding the sandpaper on table 53. The lips 54- and notches 56 provide an extremely simple and reliable means for holding a sheet of sandpaper, and the paper may be mounted on and removed from the table very quickly and conveniently. The member 52 further has a. pair of flexible arms 57, one on each side having enlarged ends 58 by which member 52 is mounted. Although two arms 57 are shown, it is possible that only one arm, centrally located, would also work satisfactorily. Each of the enlarged ends 58 of arms 57 has concentric openings 59, 61 for loosely receiving a pin 62 and upper end 63 respectively of a mounting post 64 as best seen in FIG. 3. The posts 64 are shown secured to stator 22 by a press fit or the like, although any other suitable means for securing posts 64 to stator 22 may be used. Each of the arm ends 53 has a beveled surface or projection 65 inclined several degrees with respect to the horizontal, and an annular boss 66 around which one end of a helical spring 67 is mounted, one end of spring 67 bearing against beveled surface 65 and its opposite end ibeaning against housing 15. The spring 67 is under slight compression and by virtue of surface 65 as seen in FIG. tends to apply a force moment to arms 57 urging the arms and table 53 downwardly toward motor shaft 25 and pin 26. The lower surface of table 53 has an elongated slot 68 for receiving the eccentrically mounted pin 26, and by virtue of springs 67, the eccentric pin 26 and slot 68 connection is assured.

The front end of housing 16 further has an integrally formed shelf 69 as best seen in FIG. 3 for receiving a sponge 71 or the like by which the lead may be wiped after it is sharpened. This serves to remove all loose lead filings that tend to adhere to the lead tip. The shelf further has an opening 72 through which the lead filings may be emptied from the enclosure after sponge 71 is removed for those cases in which housing 16 is sealed to base 14.

To prevent motor 21 from being contaminated by the lead filings which accumulate in the enclosure, and which may tend to interfere with the proper operation of the motor and hence assure long trouble-free service of sharpening device 13, the motor 21 is enclosed within a plastic membrane 73 as seen in FIG. 3. This is preferably accomplished by placing membrane 73 around the motor 21 and its parts, and then evacuating the air beneath the membrane causing it to tightly encircle motor 21.

In the operation of this invention, let us assume inidaily that the sharpening device 13 is placed within easy reach of the operator and that electrical plug 51 is inserted into a suitable receptacle connecting the power supply to device 13. Let us assume also that cover 27 is in a closed position. In this position, switch 33 is open and hence motor 21 is unenergized, and device 13 is in a normally inoperative position. Let us assume that the operator, who may be a draftsman or an architect or the like, has been using a compass and the lead held therein has become dulled. The operator then merely moves cover 27 into the open position, automatically closing switch 33 and energizing motor 21 causing member 52 to be reciprooated by virtue of the connection between slot 28 and eccentrically mounted pin 26. In order for member 52 to reciprocate, arms 57 must be flexible and in the preferred embodiment, table 53 has been slotted at 74 adjacent each side to lengthen arms 57, and the slots 74 terminate in a circular opening 75 of a predetermined radius to reduce the cross-sectional thickness of each arm 57 at that end and hence increase its flexibility. The arms 57 must be flexible enough so that the load on motor 21 is not excessive, and yet it must be strong enough to be able to Withstand the constant flexing and unflexing to which they are subjected. The operator then sharpens the compass lead on the sandpaper 55 mounted on reciprocating table 53, wipes the sharpened lead on the wiping pad 71, and then closes cover 27 deenergizing motor 21. The lead filings work their way off the edges of table 53 and fall down into the enclosure.

The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected Within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. In a lead sharpening device for a pencil or the like, the combination comprising:

(A) a motor;

(B) a rotatable eccentric pin driven by said motor; and

(C) a unitary U-shaped member having (1) a pair of spaced apart flexible arms extending in one direction and (2) a rectangular table transverse to said arms and interposed therebetween for releasably holding a piece of sand paper, one end of each of said arms being integral with one end of said table and the opposite end of each arm being pivotally mounted to said device, said table further having an elongated slot for receiving said eccentric whereby said table is reciprocally driven along a predetermined path upon rota- I tion of said eccentric.

2. The invention according to claim 1 wherein said opposite end of each arm is pivotally mounted on a projection and has a beveled surface, and a spring is interposed between said device and each of said beveled srn'faces for holding said opposite end on said projection and urging said member into engagement with said eccentric.

References Cited in the file of this patent UNITED STATES PATENTS 2,075,474 Scutt Mar. 30, 1937 2,791,986 'I aylor May 14, 1957 FOREIGN PATENTS 191,470 Great Britain Jan. 12, 1923 624,331 Great Britain June 2, 1949 

1. IN A LEAD SHARPENING DEVICE FOR A PENCIL OR THE LIKE, THE COMBINATION COMPRISING: (A) A MOTOR; (B) A ROTATABLE ECCENTRIC PIN DRIVEN BY SAID MOTOR; AND (C) A UNITARY U-SHAPED MEMBER HAVING (1) A PAIR OF SPACED APART FLEXIBLE ARMS EXTENDING IN ONE DIRECTION AND (2) A RECTANGULAR TABLE TRANSVERSE TO SAID ARMS AND INTERPOSED THEREBETWEEN FOR RELEASABLY HOLDING A PIECE OF SAND PAPER, ONE END OF EACH OF SAID ARMS BEING INTEGRAL WITH ONE END OF SAID TABLE AND THE OPPOSITE END OF EACH ARM BEING PIVOTALLY MOUNTED TO SAID DEVICE, SAID TABLE FURTHER HAVING AN ELONGATED SLOT FOR RECEIVING SAID ECCENTRIC WHEREBY SAID TABLE IS RECIPROCALLY DRIVEN ALONG A PREDETERMINED PATH UPON ROTATION OF SAID ECCENTRIC. 